/*
 * This file is part of aion-emu <aion-emu.com>.
 *
 * aion-emu is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * aion-emu is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with aion-emu.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.aionemu.gameserver.ai.desires;

import com.aionemu.gameserver.ai.AI;

/**
 * This interface represents basic desire functions.<br>
 * Each desire should implement {@link #handleDesire(com.aionemu.gameserver.ai.AI)} method with default behaviour.<br>
 * AI can override {@link com.aionemu.gameserver.ai.AI#handleDesire(Desire)} to implement custom behaviour of desire.<br>
 * 
 * @author SoulKeeper
 * @modified ATracer
 * @see com.aionemu.gameserver.ai.AI
 * @see com.aionemu.gameserver.ai.AI#handleDesire(Desire)
 * @see com.aionemu.gameserver.ai.desires.AbstractDesire
 */
public interface Desire extends Comparable<Desire>
{

	/**
	 * Invokes default desire action. AI can override invocation of this method to handle desire in it's own way
	 * 
	 * @param ai
	 *            actor that is doing this desire
	 */
	boolean handleDesire(AI<?> ai);

	/**
	 * Returns hashcode for this object, must be overrided by child
	 * 
	 * @return hashcode for this object
	 */
	int hashCode();

	/**
	 * Compares this Desire with another object, must overriden by child
	 * 
	 * @param obj
	 *            another object to compare with
	 * @return result of object comparation
	 */
	boolean equals(Object obj);

	/**
	 * Returns desire power of this object
	 * 
	 * @return desire power of the object
	 */
	int getDesirePower();

	/**
	 * Adds desire power to this desire, this call is synchronized.<br>
	 * <br>
	 * <b>WARNING!!! Changing desire power after adding it to queue will not affect it's position, you have to call
	 * {@link com.aionemu.gameserver.ai.desires.DesireQueue#addDesire(Desire)} passing this instance as argument</b>
	 * 
	 * @param desirePower
	 *            amount of desirePower to add
	 * @see DesireQueue#addDesire(Desire)
	 */
	void increaseDesirePower(int desirePower);

	/**
	 * Reduces desire power by give amount.<br>
	 * <br>
	 * <b>WARNING!!! Changing desire power after adding it to queue will not affect it's position, you have to call
	 * {@link com.aionemu.gameserver.ai.desires.DesireQueue#addDesire(Desire)} passing this instance as argument</b>
	 * 
	 * @param desirePower
	 *            amount of desirePower to substract
	 * @see DesireQueue#addDesire(Desire)
	 */
	void reduceDesirePower(int desirePower);
	
	/**
	 *  Used in desire filters
	 */
	boolean isReadyToRun();
	
	/**
	 * Will be called by ai when clearing desire queue.
	 */
	void onClear();
}